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Old Monday 1st June 2020, 15:14   #1
KenM
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Thought this was interesting?

Caught this in a shutter-burst this am. Interesting that an essentially all dark bird should at a given angle show white reflection on the almost flat under-wing surfaces and tail, and not even a glint off the barrelled body.
Presume there must be a ''physics/material'' answer to this?

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Old Monday 1st June 2020, 15:41   #2
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Can’t help with the scientific reason but bright sunlight on the darker plumaged birds makes the wings ‘shine‘ to our eyes, I have a few silver-winged Ravens here!
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Old Monday 1st June 2020, 16:11   #3
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Different textures and physical structure of body and wing feathering. Very common effect in photos.

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Old Monday 1st June 2020, 16:14   #4
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Can’t help with the scientific reason but bright sunlight on the darker plumaged birds makes the wings ‘shine‘ to our eyes, I have a few silver-winged Ravens here!
Yes dark clouds and corvids often have a silver lining...and yet the “barrelled body” doesn’t appear to reflect any glare.
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Old Monday 1st June 2020, 17:22   #5
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Yes dark clouds and corvids often have a silver lining...and yet the “barrelled body” doesn’t appear to reflect any glare.
I think that's what John was alluding to, the body is a mass whereas the wing feathers are err, light as a feather (no blood, organs etc) and at times transparent at times reflective
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Old Monday 1st June 2020, 18:05   #6
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I think that's what John was alluding to, the body is a mass whereas the wing feathers are err, light as a feather (no blood, organs etc) and at times transparent at times reflective
Body feathering is a lot less structured as well. Much of it is quite loose and multi-directional fibres reflecting light in multiple directions and for that matter allowing some to pass through and be lost in inner layers.

Flight feathers are highly organised rows of barbs zipped together forming a surface that is effectively designed to reflect in only a few particular directions if hit by light at a particular angle. When that angle applies a lot of light is reflected in a fairly focused manner.

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Old Monday 1st June 2020, 18:07   #7
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Yes thanks all, a very odd looking Swift, it’s the white forked tail with the black centre spine that looks to my eye at least quite unusual.

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Old Monday 1st June 2020, 20:27   #8
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Yes thanks all, a very odd looking Swift, it’s the white forked tail with the black centre spine that looks to my eye at least quite unusual.

Cheers
Well not an ‘odd looking Swift’ as such, but an odd looking photo of a Swift - in addition to what others have said about the natural phenomena of light on black plumage, I think a certain amount of overexposure when taking a shot (ie where light strongly hits one surface more than the rest of the frame) can also burn out subtle colour and detail so can produce odd artefacts in a photo.

It is interesting (and a cautionary tale for ID purposes!)
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Old Monday 1st June 2020, 20:54   #9
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Yes thanks all, a very odd looking Swift, it’s the white forked tail with the black centre spine that looks to my eye at least quite unusual.

Cheers
But it isn't that monochrome effect all the time though Ken, just certain angles and light reflection as Deb and others have explained. I would hazard a guess that other frames in your "burst" show a bird that has dark wings and tail concolorous with the body. It is a snapshot and we know how just one image can deceive, play tricks or even suggest it is something else.
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Old Monday 1st June 2020, 22:02   #10
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Remiss of me, I failed to state the obvious...ie it’s the image and NOT the Swift that’s odd looking!
I was looking at it from an “impressionistic” point of view, whilst also considering the science (dynamics of light and mass) producing such an image.

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Old Tuesday 2nd June 2020, 19:33   #11
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Remiss of me, I failed to state the obvious...ie it’s the image and NOT the Swift that’s odd looking!
I was looking at it from an “impressionistic” point of view, whilst also considering the science (dynamics of light and mass) producing such an image.

Cheers
Na. I understood what you meant. I agree it's interesting as an illusion. I also like John's summing up of the physics behind the snapshot. I never forget that photography essentially means 'writing with light' and how the camera was a doorway for me to become interested in the phenomenon of light in and of itself.
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Old Tuesday 2nd June 2020, 19:45   #12
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Remiss of me, I failed to state the obvious...ie it’s the image and NOT the Swift that’s odd looking!


Cheers
Are you being overly sensitive Ken ? There was a wink after my comment - I was just being being pedantic
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Old Tuesday 2nd June 2020, 22:47   #13
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Are you being overly sensitive Ken ? There was a wink after my comment - I was just being being pedantic
Me sensitive Deb?....Nah!...got skin like a rhino.
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Old Wednesday 3rd June 2020, 01:52   #14
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In addition to what others have said, the underside of the flight feathers is remarkably glossy on Common Swift (with an almost waxy feel to the feathers), while its body feathers are more matte (hence the strong contrast on your pic: part of the plumage reflects light, while other part absorbs light). See here for example: http://blascozumeta.com/wp-content/u...7.apusapus.pdf
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Old Wednesday 3rd June 2020, 07:01   #15
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Me sensitive Deb?....Nah!...got skin like a rhino.
Moisturise daily

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Old Wednesday 3rd June 2020, 07:19   #16
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Moisturise daily

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He does, with 60% proof, but that’s internally ( and purely for medicinal purposes of course)
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Old Wednesday 3rd June 2020, 13:14   #17
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In addition to what others have said, the underside of the flight feathers is remarkably glossy on Common Swift (with an almost waxy feel to the feathers), while its body feathers are more matte (hence the strong contrast on your pic: part of the plumage reflects light, while other part absorbs light). See here for example: http://blascozumeta.com/wp-content/u...7.apusapus.pdf
Thanks Rafael....if only I could read Spanish.

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Moisturise daily

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Am currently doing just that John! due to the “soddingly high” pollen count!

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He does, with 60% proof, but that’s internally ( and purely for medicinal purposes of course)
Twice a week only Richard and at just 11% alcohol!....anything stronger could impede my performance “out doors”.
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Old Wednesday 3rd June 2020, 14:46   #18
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Thanks Rafael....if only I could read Spanish.



Am currently doing just that John! due to the “soddingly high” pollen count!



Twice a week only Richard and at just 11% alcohol!....anything stronger could impede my performance “out doors”.
Are these the days (daze) when we get the 'odd' birds by any chance?
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Old Wednesday 3rd June 2020, 14:53   #19
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Are these the days (daze) when we get the 'odd' birds by any chance?
Yesh, after my pre dinner Pastis (51% alcohol, water with it of course) I thought I saw a Pink eared Duck yeshterday
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Old Wednesday 3rd June 2020, 14:53   #20
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Thanks Rafael....if only I could read Spanish.
I meant the photos Ken (especially those in page 6, showing the underwing, that you can magnify), nothing relevant in the text for this thread.
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Old Wednesday 3rd June 2020, 15:45   #21
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Are these the days (daze) when we get the 'odd' birds by any chance?
Well “odd” birds are better than no birds Andy.

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I meant the photos Ken (especially those in page 6, showing the underwing, that you can magnify), nothing relevant in the text for this thread.
A-h-h! apologies Rafael, I appear to have exceeded the brief.

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Yesh, after my pre dinner Pastis (51% alcohol, water with it of course) I thought I saw a Pink eared Duck yeshterday
That’s probably the only way you’ll add a 2nd species of duck to your annual grdn.list Richard.
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